Reciprocating compressor having a discharge pulsation reducing structure

ABSTRACT

Disclosed is the reciprocating compressor according to the present invention comprising a main frame disposed inside a case to support an electrically-driven unit, a cylinder block connected with the main frame and having a compression chamber, a cylinder head having a refrigerant discharge chamber and connected with the cylinder block to seal the compression chamber, a first discharge muffler disposed at one side of the cylinder block, a second discharge muffler connected with a refrigerant discharge pipe and disposed at other side of the cylinder block, a refrigerant path connecting the refrigerant discharge chamber and the first discharge muffler, and a connecting path formed to penetrate the cylinder block to connect the first discharge muffler and the second discharge muffler.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates generally to a reciprocating compressor, and more particularly, to reciprocating compressors having a discharge pulsation reducing structure for reducing noise made by the discharge of refrigerant.

[0003] 2. Description of the Related Art

[0004] A general or conventional reciprocating compressor is used in refrigerating machines, such as refrigerators and water cooling machines, for compressing low pressure gas refrigerant into high pressure refrigerant.

[0005] As shown in FIG. 1, a reciprocating compressor comprises mainly a case 10 having an upper shell 11 and a lower shell 12, a compression unit 30 disposed inside the lower part of the compressor and comprised of apparatuses for compressing refrigerant, and an electrically-driven unit 20 for driving the compression unit 30.

[0006] The compression unit 30 further comprises a cylinder head 60 having a refrigerant suction chamber 61 and a refrigerant discharge chamber 62, a cylinder block having a compression chamber 71 in which refrigerant is compressed, a valve assembly 80 controlling the flow of refrigerant between the cylinder head 60 and the cylinder block 70, a piston 50 disposed inside the compression chamber 71, and a connecting rod 40 moving the piston 50 to reciprocate linearly.

[0007] The electrically-driven unit 20 for driving the compression unit 30 comprises a stator 21 fixed to the case 10, a rotor 22 rotating by the electromagnetic reciprocating operation with the stator 21, and a crank shaft 23 press-fit in the rotor 22 and having an eccentric portion 23 a. The eccentric portion 23 a is connected to the connecting rod 40.

[0008] As shown in FIG. 2, a protruding discharge muffler 72 is provided at the bottom of the cylinder block 70. The discharge muffler 72 is connected with a refrigerant discharge pipe 74, which is itself connected to a condenser (not shown) and the discharge muffler 72 is sealed by a muffler cover 73. In addition, the discharge muffler 72 is in fluid communication with a refrigerant path 75 formed through the cylinder block 70. The refrigerant in the refrigerant discharge chamber 62 is thus enabled to flow into the discharge muffler 72 through the refrigerant path 75.

[0009] In the above conventional compressor, the refrigerant flows into the compression chamber 71 sequentially through a refrigerant suction pipe 91, a muffler 90, and the refrigerant suction chamber 61 and is then discharged into the refrigerant discharge chamber 62 after being compressed by linear reciprocation of the piston 50. The refrigerant discharged into the refrigerant discharge chamber 62 flows into the discharge muffler 72 through the refrigerant path 75 and then into the condenser through the refrigerant discharge pipe 74.

[0010] However, in such conventional reciprocating compressor, discharge pulsation occurs because the piston 50 in the compression chamber 71 sucks in, compresses, and discharges the refrigerant while it is linearly reciprocating. Such discharge pulsation of the refrigerant causes noise and vibration of the compressor. Particularly, since the vibration of the compressor occurs at the acoustic low frequency band corresponding to the natural frequency of other parts of a refrigerator, the vibration creates resonance with other parts of the refrigerator, and thereby causes noise and vibration to increase in the overall refrigerator.

[0011] The discharge pulsation of such refrigerant may be reduced by increasing the flow resistance of the discharge refrigerant. That is, the discharge pulsation of the refrigerant may be reduced by reducing the sectional area of the refrigerant path 75 between the refrigerant discharge chamber 62 and the discharge muffler 72, or by lengthening the refrigerant path 75. However, when the sectional area of the refrigerant path 75 is too small, the refrigerant cannot flow smoothly between the refrigerant discharge chamber 62 and the discharge muffler 72, and therefore the compression efficiency of the compressor drops. In addition, the refrigerant cannot be sufficiently lengthened as it is formed through the cylinder block 70, which is predetermined by the compressor construction design.

SUMMARY OF THE INVENTION

[0012] In order to solve the above-mentioned problem, the present invention has been developed to provide a reciprocating compressor capable of efficiently reducing the discharge pulsation by improving the refrigerant discharge structure.

[0013] In order to achieve the object of the present invention, the reciprocating compressor comprises a main frame disposed inside a sealed case to support an electrically-driven unit, a cylinder block connected with the main frame and having a compression chamber, a cylinder head having a refrigerant discharge chamber and being connected with the cylinder block to seal the compression chamber, a first discharge muffler disposed at one side of the cylinder block, a second discharge muffler connected with a refrigerant discharge pipe and disposed at another side of the cylinder block, a refrigerant path connecting the refrigerant discharge chamber and the first discharge muffler, and a connecting path formed to penetrate the cylinder block to connect the first discharge muffler and the second discharge muffler.

[0014] It is preferable that, in the present invention having the above structure, the connecting path is formed having a V shape and may have a necked shape.

[0015] In addition, it is preferable that the diameter of the connecting path is between about 1.5 mm and 4.0 mm.

[0016] It is also preferable that the height of the first and second discharge mufflers is between about 14 mm and 30 mm and the volume of the first and second muffler is between about 18 cc and 25 cc.

[0017] Moreover, it is preferable that the cylinder block is screwed to the main frame and connected to the main frame by a first screw penetrating the first discharge muffler and being tightened on the main frame and a second screw penetrating the second discharge muffler and being tightened on the main frame.

BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The aforementioned object and characteristic of the present invention will be more apparent by referring to a description of a preferred embodiment of the present invention with reference to the accompanying drawings, in which:

[0019]FIG. 1 is a cross-sectional view showing structure of a conventional reciprocating compressor;

[0020]FIG. 2 is a partially cut-away bottom view of the conventional reciprocating compressor of FIG. 1;

[0021]FIG. 3 is a perspective view of a part of the reciprocating compressor according to a preferred embodiment of the present invention; and

[0022]FIG. 4 is a cross-sectional view of the part of the reciprocating compressor, taken approximately along a line A-A of FIG. 3.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0023] Hereinafter, a preferred embodiment of the present invention will be described in greater detail with reference to the accompanying drawings. As the structure of the reciprocating compressor according to the present invention is identical to the conventional reciprocating compressor shown in FIG. 1, except for some structural elements, the identical parts will be given the same reference numbers.

[0024] As shown in FIGS. 3 and 4, the reciprocating compressor according to the present invention comprises a main frame 24, a cylinder block 100, first and second discharge mufflers 110, 120, and a connecting path 130.

[0025] The main frame 24 is disposed inside the case 10 (FIG. 1) to support the electrically-driven unit 20 comprising the stator 21, the rotor 22, and the crank shaft 23, essentially as in the conventional reciprocating compressor shown in FIG. 1.

[0026] The cylinder block 100 substitutes for the cylinder block 70 of the conventional reciprocating compressor shown in FIG. 1, and comprises the compression chamber 101 in which the piston 50 (FIG. 1) connected with the connecting rod 40 (FIG. 1) reciprocates linearly. The cylinder block 100 is connected with the main frame 24 by first and second screws 103, 104. The compression chamber 101 is sealed against the cylinder head 60 (FIG. 1) having the refrigerant discharge chamber 62 (FIG. 1). The compression chamber 101 is united with the cylinder block 100. The valve assembly 80 (FIG. 1) is disposed between the cylinder block 100 and the cylinder head 60.

[0027] The first and second discharge mufflers 110, 120 (FIG. 4) are disposed adjacent opposite sides of the cylinder block 100. The first discharge muffler 110 is connected with the refrigerant discharge chamber 62 of the cylinder head 60 by the refrigerant path 102 formed in the cylinder block 100. The second discharge muffler 120 is connected with the first discharge muffler 110 and the refrigerant discharge pipe 140, connected with the condenser, is connected to it. In addition, the first and second discharge mufflers have a predetermined volume to diminish resonance caused by the flow of refrigerant. It is preferable that the discharge mufflers 110, 120 are between about 14 mm and 30 mm high and have a volume between about 15 cc and 25 cc.

[0028] In addition, connected to the upper opening of the first discharge muffler 110 is a first muffler cover 111 having a through hole 112, and formed at the bottom of the first discharge muffler 110 is a screw hole 113. Similarly, connected to the upper opening of the second discharge muffler 120 is a second muffler cover 121 having a through hole 122, and formed at the bottom of the second discharge muffler 120 is a screw hole 123. One end of the refrigerant discharge pipe 140 penetrates the second muffler cover 121 and is inserted into the second discharge muffler 120.

[0029] Meanwhile, the first screw 103 penetrates the first muffler cover 111 through the through hole 112 and is fastened to the main frame 24 as it is inserted into the screw hole 113 of the first discharge muffler 110. The second screw 104 penetrates the second muffler cover 121 through the through hole 122 and is fastened to the main frame 24 as it is inserted into the screw hole 123 of the second discharge muffler 120. Therefore, the discharge mufflers 110, 120 are each sealed by the first and second muffler covers 111, 121, respectively, and the cylinder block 100 is connected with the main frame 24.

[0030] The connecting path 130 penetrates the cylinder block 100 so as to connect the first discharge muffler 110 to the second discharge muffler 120. The connecting path 130 has a V shape so as to reduce the discharge pulsation of the refrigerant. In addition, the connecting path 130 can reduce the discharge pulsation more effectively by having a necked shape, that is, it is configured having a reduced diameter for at least a portion of the path.

[0031] The inner diameter of the connecting path 130 has a size determined considering the occurrence of the discharge pulsation. When the inner diameter of the connecting path 130 is large, the efficiency of the connecting path 130 reducing the discharge pulsation decreases and when too small, the compression efficiency of the compressor decreases as the flow resistance of the refrigerant increases. Accordingly, the diameter of the connecting path 130 should be determined in an appropriate size and it is preferable that the size is between about 1.5 mm and 4.0 mm.

[0032] The discharge process of the compressed refrigerant of the reciprocating compressor having the above described structure according to the present invention is described in operation below.

[0033] When the piston 50 retrogrades toward the bottom dead point inside the compression chamber 101 by the rotation of the crank shaft 23, the low pressure refrigerant flown into the suction muffler 90 (FIG. 1) through the suction pipe 91 (FIG. 1) flows into the compression chamber 101 through the refrigerant suction chamber 61 of the cylinder head 60. After that, when the piston 50 moves toward the top dead point inside the compression chamber 101 as the crank shaft further rotates, the refrigerant is compressed and achieves high pressure.

[0034] The compressed refrigerant is temporarily stored in the refrigerant discharge chamber 62 of the cylinder head 60 and then flows into the first discharge muffler 110 through the refrigerant path 102 of the cylinder block 100. The refrigerant in the first discharge muffler 110 then flows into the second discharge muffler 120 through the connecting path 130 and then again into the condenser (not shown) through the refrigerant discharge pipe 140.

[0035] In the process of discharging the refrigerant, the discharge pulsation decreases as the compressed refrigerant flows into the first discharge muffler 110 having a predetermined size and volume through the refrigerant discharge chamber 62 of the cylinder head 60 and again as it flows from the first discharge muffler 110 into the second discharge muffler 120 through the V shaped connecting path 130.

[0036] Additionally, the reciprocating compressor according to the present invention has an effect on suppressing the vibration of the compressor caused by the flow of the refrigerant, since the connecting path formed in the V shape, which becomes a path for the refrigerant to flow along from the first discharge muffler to the second muffler, penetrates the inside of the cylinder block.

[0037] Furthermore, the reciprocating compressor according to the present invention is effective in reducing the overall vibration of the compressor as the vibration made in the cylinder block is not passed on to the main frame easily for the reason that the main frame and the cylinder block, which are the separate parts, are connected by screws, and not integral.

[0038] Moreover, according to the present invention the manufacturing costs can be reduced because the main frame and the cylinder block are separately produced as parts having a simple shape and then easily assembled.

[0039] Although the preferred embodiment of the present invention has been described, it will be understood by those skilled in the art that the present invention should not be limited to the described preferred embodiment. Various changes and modifications can be made so as to remain within the sprit and scope of the present invention as defined by the appended claims. 

What is claimed is:
 1. A reciprocating compressor comprising: a main frame disposed inside a case to support an electrically-driven unit; a cylinder block connected with the main frame and having a compression chamber; a cylinder head having a refrigerant discharge chamber and being connected with the cylinder block to seal the compression chamber; a first discharge muffler disposed at one side of the cylinder block; a second discharge muffler connected with a refrigerant discharge pipe and disposed at another side of the cylinder block; a refrigerant path connecting the refrigerant discharge chamber and the first discharge muffler; and a connecting path penetrating the cylinder block to connect the first discharge muffler and the second discharge muffler.
 2. The reciprocating compressor of claim 1, wherein the connecting path is formed having a V shape.
 3. The reciprocating compressor of claim 2, wherein the connecting path has a necked shape.
 4. The reciprocating compressor of claim 2, wherein diameter of the connecting path is between about 1.5 mm and 4.0 mm.
 5. The reciprocating compressor of claim 2, wherein height of the first and second discharge mufflers is between about 14 mm and 30 mm.
 6. The reciprocating compressor of claim 2, wherein volume of the first and second mufflers is between about 18 cc and 25 cc.
 7. The reciprocating compressor of claim 2, wherein diameter of the connecting path is between about 1.5 mm and 4.0 mm, the height of the first and second discharge mufflers is between about 14 mm and 30 mm, and volume of the first and second mufflers is between about 18 cc and 25 cc.
 8. The reciprocating compressor of claim 1, wherein the cylinder block is connected to the main frame by means of a screw connection.
 9. The reciprocating compressor of claim 8, wherein the cylinder block is connected to the main frame by a first screw penetrating the first discharge muffler and being tightened on the main frame and a second screw penetrating the second discharge muffler and being tightened on the main frame. 